*{
    margin:0px;
    padding:0px;
}
.header{
    width: 100%;
    height: 55px;
    position: relative;
    background-color: aqua;
}
.logo{
    width: 200px;
    height:55px;
    position: absolute;
  	top: 50%;
	left: 50%;
  	margin-top: -25px; /* 高度的一半 */
  	margin-left: -25px; /* 宽度的一半 */
}
.main {
    width: 500px;
    height: 870px;
    margin: 10px auto;
}
.main_top{
    width: 500px;
    height: 50px;
}
.main_top > p {
    margin-top: 5px;
    opacity: 0.6;
    font-size: 12px;
}
h3{
    color:#505050;
}

.main_center{
    width: 500px;
    height: 540px;
    margin-top: 10px;

}

.main_center > img {
    width: 500px;
    height: 250px;

}
.main_center>div{
    width:500px;
    height: 250px;
    margin-top: 15px;
    margin-bottom:10px;
}
.main_center  >div> p{
    font-size: 12px;
    line-height: 25px;
}
.p_fifth,.p_third{
    text-indent: 2em;
}
.main_buttom{
    width: 500px;
    height: 250px;
}

.td_first{
    font-size: 13px;
    text-align: center;
    width: 100px;
    height: 30px;
    color: black;
    font-weight: bold;
}
.td_second{
    width:400px;
    text-align: center;
    font-size:12px;
}
